Reproductive and lifestyle risk factors and mammographic density in Mexican women

Several breast cancer risk factors have been consistently associated with mammographic density (MD); however, data are limited for Hispanic women.

We examined data from 1007 premenopausal and 600 postmenopausal women in the Mexican Teachers' Cohort. Multivariable linear regression was used to estimate associations between risk factors and MD.

Among premenopausal women, age, current body mass index (BMI), BMI at age 18 years, and weight change since age 18 years were inversely associated with percent MD, whereas benign breast disease, alcohol intake, and breastfeeding 12 months or more were associated with higher percent MD. Among postmenopausal women, age, current BMI, BMI at age 18 years, weight change since age 18 years, and speaking or having parents who speak an indigenous language were inversely associated with percent MD, whereas benign breast disease and greater age at natural menopause were positively associated with percent MD. Other breast cancer risk factors, such as age at menarche, parity, and age at first pregnancy, were not significantly associated with density in either premenopausal or postmenopausal women.

Results from the Mexican Teachers' Cohort are generally consistent with predictors of mammographic density observed in primarily non-Hispanic white populations; however, certain risk factors (e.g., parity) were not significantly associated with MD.